Many modern vehicles are provided with components designed to manage vehicle emissions into the atmosphere. For example, some vehicles include particulate filters associated with the vehicle exhaust system for filtering exhaust fluid produced by the engine. A variety of such filters are known.
One issue presented by some exhaust particulate filters is that they may lose filtering capability or become ineffective if the filter is not regenerated. It is possible, for example, for the filter to become plugged if accumulated soot is not purged from the filter. In many cases filter regeneration occurs passively as the heat of the vehicle exhaust is sufficient for filter regeneration during the normal course of vehicle operation. In some cases, however, the vehicle is used in a manner that the vehicle exhaust does not become hot enough for a sufficiently long time to achieve filter regeneration. Proposals have been made for addressing such a situation.
One proposal is shown in U.S. Pat. No. 8,136,505. That proposal is to retard the spark angle at which spark is delivered to a cylinder of the vehicle engine to increase the temperature of the exhaust and the particulate filter. Even if such a spark control is used, however, it is possible that it will not have the desired effect. Additional measures may be needed to ensure that temperatures sufficient for regeneration are reached for a sufficient time. Additionally, new governmental regulations are being imposed that place new restrictions on vehicle emissions and previously proposed approaches may not satisfy such new standards.